A doctor who worked at a prestigious Massachusetts boarding school is finalizing a plea deal with prosecutors in a child pornography case.

Richard Keller pleaded not guilty last year to possessing and receiving child pornography. Authorities say he received some of it at the student health center at Phillips Academy in Andover, where he was the medical director for 19 years.

Prosecutors and Keller's attorney filed a report in court this week saying they have reached an agreement in principle on a plea deal. They asked to schedule a change-of-plea hearing for next month to give them time to complete details.

Keller's lawyer and a spokeswoman for U.S. Attorney Carmen Ortiz declined to say whether Keller will plead guilty to all three charges or whether they will make a joint sentencing recommendation.